Dental implant

ABSTRACT

The present invention provides a dental implant including: a fixture and an abutment including a coupling leg, and the fixture and the abutment are elastically coupled with each other, the dental implant including: a fixture axial hole inner inclined surface in which an inner diameter of an axial hole is gradually and downwardly reduced from a predetermined position of an inner inclined surface of the fixture; a first coupling part formed with a coupling hole at a predetermined position of the fixture; and a first associated coupling part formed with a coupling protrusion complementarily coupled with the first coupling part, wherein when the first associated coupling part is separated from the first coupling part by rotating the abutment, the coupling protrusion upwardly pushes the abutment from the fixture by elastic repulsion with the axial hole inner inclined surface of the fixture, thus the abutment becomes separated from the fixture.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation from U.S. patent application Ser. No.15/568,647 filed Oct. 23, 2017 (now allowed), which was a 371application for international patent application PCT/KR2016/007063having the same title, and is related to and claims priority from KoreaPatent Application 10-2015-0099671 filed Jul. 14, 2015 which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a dental implant fixing a dentalprosthesis by forming an artificial tooth root that is coupled andimplanted in the alveolar bone. More particularly, the present inventionrelates to a dental implant whereby an abutment is easily separated froma fixture of the dental implant, and vertical occlusal force appliedthereto may be efficiently absorbed by improving a coupling structurebetween the fixture and the abutment.

BACKGROUND ART

In dentistry, an implant means an artificial tooth substituting for alost natural tooth or a dental procedure that is conducted in such amanner that a fixture is implanted into a jawbone to be fused with thejawbone for a predetermined period, and prostheses such as a couplingmember, artificial teeth, and the like are then fixed thereon so thatthe original functions of teeth can be recovered.

Although a typical prosthetic appliance or a typical false tooth damagessurrounding teeth or bones according to the elapse of the time, animplanted tooth does not damage a surrounding tooth structure, andperforms the function of an original tooth in the same shape as that ofthe original tooth. In addition, the implanted tooth is not decayed, sothat the implanted tooth can be used for a long time.

Also, implants may facilitate the recovery of a single missing tooth andimprove the function of an artificial tooth for a partially orcompletely edentulous patient, and may improve dental prosthesisrecovery in terms of aesthetics. Furthermore, implants disperse anexcessive stress applied on tissues of a support bone therearound, andcontribute to stabilization of teeth in a row.

In the case of such an implant, a fixture implanted into a jawbone iscoupled with a coupling part of an abutment with an upper axial hole ofthe fixture, and prosthesis is fixed on an upper part of the abutment.

In a conventional implant structure, a fixture and an abutment arethread-coupled, or a coupling hole of the fixture and a couplingprotrusion of the abutment are elastically and complementarily coupled.

In a conventional thread-coupled structure, when a continuous load isrepeatedly generated within the mouth as an implant wearer chews food,the screw coupling state becomes loose by being rotated since the screwslightly vibrates, and the oscillation width is gradually increased.Accordingly, a gap between the fixture and the abutment is generated. Inother words, the artificial tooth shakes, thus the implant user may noteasily chew the food, and undesirable mastication pressure may occuraround the artificial tooth.

In addition, in the conventional implant structure, as described above,when coupling the abutment with the fixture, a thread-coupling may beperformed while an accurate coupling position is not found. Accordingly,the artificial tooth and the alveolar bone may be damaged.

In addition, an implant unit having the above conventional implantstructure has many difficulties in coupling the screw within a narroworal cavity. Particularly, in the case of a patient whose surgical areais located on the back teeth side or who cannot widen his or her mouthwidely, the implant procedure becomes more difficult.

As a conventional technique for solving such conventional problems, adental implant of Korean Patent No 10-0668368 has been proposed.

In the conventional technique, a dental implant includes: a fixturehaving an axial hole in an upper portion thereof and implanted into ajawbone; and an abutment having coupling legs made of a shape memoryalloy, the legs being inserted into the axial hole of the fixture in alower portion thereof and elastically coupled with the fixture so thatteeth can be used to chew food. Herein, in the conventional technique, acoupling hole of the fixture formed with a concave form in an axial holeinner surface is formed in a vertical surface of the fixture innersurface.

Elastic coupling structures between the fixture and the abutment of theconventional technique have realized much technical advancement byeffectively improving the thread-coupling problems. In addition, inactual use, it is very convenient to use since the coupling protrusionof the coupling leg is automatically and elastically coupled with thecoupling hole of the fixture when the abutment is inserted within thefixture.

However, the above elastic coupling structures between the fixture andthe abutment of the conventional technique cause inconvenience whenseparating the abutment from the fixture, and are not able toeffectively perform buffer functions when vertical occlusal force isapplied.

In other words, in order to separate the abutment from the fixture, theabutment is upwardly pulled with respect to the fixture by force suchthat the coupling protrusion or the coupling hole formed in the couplingleg is detached from the coupling hole or the coupling protrusion thatis formed in the axial hole inner surface of the fixture in associationby being upwardly pulled, or the abutment is separated from the fixtureby rotating the abutment with respect to the fixture and upwardlypulling the fixture.

However, upwardly pulling the abutment with respect to the fixture byforce as described above may apply large force to the alveolar bone ofthe patient through the fixture. As a result, there is great risk ofdamaging the alveolar bone of the patient due to excessive force. Inaddition, the associated coupling part and the coupling part which areconfigured with the coupling protrusion and the coupling hole formed inthe abutment and the axial hole inner surface of the fixture become worndown due to repeated attachments and detachments, thus coupling force isreduced. Further, there is a problem in placing an extracting devicethat separates the abutment from the fixture by separating in a verticaldirection, and which is disclosed in Korean Patent No. 10-1309417 andused when an upper surface of the fixture is deeply implanted in a gum.

As another coupling example, in an implant in which a coupling hole witha concave form is formed at positions spaced apart from each other atregular angles (for example, 90 degrees) along a circumferentialdirection from a predetermined vertical position of a fixture axial holeinner surface, and a coupling protrusion is complementarily formed in alower part of the abutment in association with the coupling hole areformed (Korean Patent No. 10-0668368), when separating the abutment fromthe fixture, the abutment is separated from the fixture by rotating theabutment with respect to the fixture in a circumferential direction,separating the coupling protrusion of the abutment from the couplinghole formed in the fixture axial hole inner surface at a predeterminedvertical position, and upwardly pulling the abutment from the fixture byforce. Herein, sine the size of the implant is small, it is not easy todetect an accurate rotation amount so as to know how much to rotate andthen pull it upwards. In some cases, there is a situation that it isre-fastened by being excessively rotated by giving too much power.Although a proper rotation is successfully performed, a considerableforce must be applied again in the vertical direction. Further, aneffective buffering function for vertical occlusal force may not beperformed.

Accordingly, in order to prevent the above problems, it is preferable touse a structure in which a coupling part is separated without beingre-coupled by the excessive rotation when the abutment is rotated withrespect to the fixture in a circumferential direction or perimeterdirection, and the abutment is separated from the fixture by upwardlypulling the abutment with less force. However, in the conventionaltechnique, it is impossible to perform a natural separation processbetween the abutment and the fixture.

In addition, in the conventional technique described above, the operatormay require a large force to upwardly pull the abutment with respect tothe fixture y force, and such a procedure may act as a considerablemental burden on the implant procedure.

In addition, in the conventional technique described above, the implantstructure may perform a buffer function for horizontal pressure, but abuffer function for vertical occlusion pressure may not be performed.Accordingly, there is a need for a structure that effectively performs abuffer function for vertical occlusion pressure. In addition, in theconventional technique described above, in order to separate theabutment from the fixture without damaging the fixture or the abutment,or the alveolar bone, an extraction device disclosed in Korean PatentNo. 10-1309417 should be used. However, when the fixture is deeplyimplanted from the upper part of the alveolar bone, the extractiondevice may not be used.

Technical Problem

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the prior art, and an object of the presentinvention is to provide an improved dental implant in which anassociated coupling part formed in a lower part of an abutment and acoupling part formed in an axial hole inner surface of a fixture inassociation with the associated coupling part are separated from eachother with less force when separating the abutment from the fixture. Inaddition, although the abutment is rotated with excessive force, thefixture and the abutment are not re-coupled by being rotated again at apredetermined angle. Further, coupling force for performing a functionof preventing a vertical directional separation in case of repeatedattachments and detachments is not reduced, and the abutment is easilyseparated from the fixture by upwardly pulling the abutment with lessforce.

In addition, another object of the present invention is to provide animproved dental implant in which an operator may easily detect aseparation state between the abutment and the fixture since the abutmentis separated by being automatically and upwardly pushed from the fixtureby rotating the abutment. Accordingly, the operator may procedure animplant procedure without difficulty and burdens.

In addition, another object of the present invention is to provide animproved dental implant in which a rotation with respect to rotationforce equal to or less than a predetermined value within the axial holeof the fixture is prevented without adding an additional rotationprevention form in the coupling axial part of the abutment. Further,another object of the present invention is to provide an improved dentalimplant in which attachments and detachments between the fixture and theabutment are easily performed even though the fixture is deeplyimplanted from an upper part of an alveolar bone.

In addition, another object of the present invention is to provide animproved dental implant in which vertical occlusal force is effectivelyabsorbed.

Hereinafter, for convenience of description, a function of preventingthe abutment being rotated with respect to the fixture for rotationforce equal to or less than a predetermined value is defined as“rotation prevention function”, and a function of preventing theabutment being separated from the fixture in a vertical direction isdefined as “vertical separation prevention function”.

Technical Solution

In order to accomplish the above object, the present invention providesa dental implant including a fixture forming an artificial tooth root bybeing implanted in an alveolar bone, and an abutment coupled with aprosthesis (crown or denture) at an upper part thereof and provided at alower part thereof with a coupling leg elastically coupled with an axialhole of the fixture by being elastically bent radially inwardly about acentral axis and restoring an original shape thereof,

the dental implant including: an inner inclined surface in touch aninner diameter of an axial hole is gradually and downwardly reduced froma predetermined position of an axial hole inner surface of the fixture;a first coupling part formed as a coupling hole outwardly depressed at apredetermined position of the inclined surface, and a first associatedcoupling part formed on an outer surface of the coupling leg formed inthe lower part of the abutment, and formed with a coupling protrusioncomplementarily coupled with the first coupling part formed in the axialhole inner inclined surface of the fixture, wherein

a rotation prevention function is performed within rotation force equalto or less than a predetermined value by complementarily coupling thefirst coupling part and the first associated coupling part, and thecoupling protrusion of the first associated coupling part isautomatically separates the abutment from the fixture by upwardlypushing the abutment from the fixture by elastic repulsion between theinclined surface formed in the axial hole inner surface of the fixturewhen the abutment is rotated in a circumferential direction while theabutment is coupled within the fixture so that the first associatedcoupling part formed with the coupling protrusion is separated from thefirst coupling part formed with the coupling hole.

Preferably, when coupling the abutment with the fixture, the couplinghole formed in the inclined surface formed in the axial hole innersurface of the fixture may be formed with a coupling hole downwardlyextending from the top of the inclined surface by a predetermineddistance so that the coupling protrusion of the associated coupling partformed in the outer surface of the coupling leg of the lower part of theabutment may easily find a coupling hole position formed in the axialhole inner inclined surface of the fixture and a coupling position ofthe fixture and the abutment may be easily found. Herein, horizontallengths in a circumstantial direction of the coupling protrusion of theassociated coupled part formed in the outer surface of the coupling legof the lower part of the abutment and the coupling hole of the couplingpart formed in the axial hole inner inclined surface of the fixtureshould be identical. However, vertical lengths thereof may be identicalor different.

Preferably, at least one first coupling part is formed on the axial holeinner inclined surface of the fixture along a circumstantial direction,and the abutment is coupled with the fixture only when the abutment isinserted into the fixture while arranging the abutment relative to thefixture at a predetermined angle.

Preferably, a surface in which the associated coupling part is formedmay be formed to have an identical slope with a slope of the axial holeinner inclined surface of the fixture. When the fixture and the abutmentare axially coupled, the coupling protrusion of the associated couplingpart formed in the outer surface of the coupling leg of the lower partof the abutment is more outwardly protruded than the axial hole innerinclined surface that is positioned at the same vertical position.

More preferably, the coupling hole that is the first coupling partoutwardly formed on the axial hole inner inclined surface of the fixtureat a predetermined part may have a slope identical to a slope of theaxial hole inner inclined surface of the fixture.

More preferably, the first coupling part is formed with a circular ornon-circular coupling hole.

More preferably, an outer surface part of the coupling leg of the lowerpart of the abutment in which the first associated coupling part isformed may have a slope identical to a slope of the axial hole innerinclined surface of the fixture.

Most preferably, the dental implant further includes: a secondassociated coupling part that is formed with a holding protrusion in alower or upper part of the first associated coupling part formed in thecoupling leg of the lower part of the abutment to be protruded radiallyoutwardly from the abutment so that performs a function of preventing avertical separation; and a second coupling part formed with a holdingportion inwardly formed on the axial hole inner surface of the fixtureso that the second coupling part is coupled in association with thesecond associated coupling part, wherein when the first coupling part iscoupled with the first associated coupling part, the second associatedcoupling part and the second coupling part are coupled at the same timeso that coupling force in an axial direction between the abutment andthe fixture is reinforced, and when the first associated coupling partis separated from the first coupling part by a rotation of the abutment,the coupling leg of the lower part of the abutment is elastically bentradially inwardly so that the second associated coupling part formedwith the holding protrusion is automatically separated from the secondcoupling part formed in the axial hole inner surface of the fixture,thus the abutment is automatically and upwardly pushed by elasticrepulsion between the coupling protrusion of the first associatedcoupling part and the shaft inner inclined surface, and the abutment andthe fixture are separated from each other.

In addition, preferably, in the present invention, the associatedsurface of the abutment in which the first associated coupling part isformed may be formed to be associated with a surface in which the firstcoupling part is formed in the axial hole inner inclined surface of thefixture.

In the present invention, the first coupling part and the secondcoupling part may be formed in the inner inclined surface together, oronly the first coupling part may be formed in the inner inclined surfaceof the axial hole of the fixture and the second coupling part may beformed in a vertical surface of the axial hole of the fixture.Meanwhile, the second coupling part that mainly performs a verticalseparation prevention function may be formed with a ring-shaped holdingportion in a concave form along the entire circumferential direction, ormay be formed at positions spaced apart from each other at regularangles along the circumferential direction (for example, 90 degrees, 120degrees, 180 degrees) as that of the first coupling part. In addition,positions of the first coupling part and the first associated couplingpart which mainly perform a rotation prevention function, and the secondcoupling part and the second associated coupling part which mainlyperform a vertical separation prevention may be vertically changed.However, herein, the coupling hole of the first coupling part of theaxial hole inner inclined surface of the fixture which mainly performs arotation prevention function should be formed on the axial hole innerinclined surface of the fixture.

In addition, in the present invention, functions of the first couplingpart that mainly performs a rotation prevention function and the secondcoupling part that mainly performs a vertical separation preventionfunction may be may be integrated in the first coupling part formed onthe axial hole inner inclined surface of the fixture to form a singlecoupling part. In other words, a coupling part formed with a couplinghole having a coupling portion may be formed in an inclined surface partformed in the axial hole inner surface of the fixture, and an associatedcoupling part formed with a coupling protrusion that is complementarilycoupled with the coupling part of the fixture is formed in the lowerpart of the abutment. Accordingly, a single coupling part and a singleassociated coupling part in which vertical separation prevention androtation prevention functions are performed at the same time, and theassociated coupling part upwardly pushes the abutment by interworkingwith the inclined surface of the axial hole inner surface of the fixturewhen the abutment is rotated while being coupled.

In addition, in the present invention, the coupling protrusion formed inthe abutment and the coupling hole formed in the axial hole innerinclined surface of the fixture may be interchanged from each other. Forexample, the associated coupling part of the abutment may be formed witha concave coupling hole, and the coupling part of the axial hole innerinclined surface of the fixture may be formed with a coupling protrusionin association thereof. Herein, the coupling hole formed in the couplingleg of the lower part of the abutment may be inwardly formed on theinner inclined surface with a diameter downwardly decreasing. Inaddition, in the present invention, installation holes may be formed inthe upper part of the abutment as shown in FIG. 1 so that the abutmentis easily rotated, a number of holes and positions thereof may be formedin association with a number of coupling legs of the lower part of theabutment and positions thereof.

Advantageous Effects

According to the present invention, the present invention includes afirst associated coupling part that mainly performs a rotationprevention function is formed in a lower part of an abutment, and afirst coupling part formed in an axial hole inclined surface of afixture at a position that is in association with the first associatedcoupling part so that the first coupling part is complementarily coupledwith the first associated coupling part.

Accordingly, according to the present invention, when separating theabutment from the fixture, the abutment and the fixture are easilyseparated by automatically and upwardly pushing the abutment from thefixture by elastic repulsion between the axial hole inner inclinedsurface of the fixture and a coupling protrusion of the first associatedcoupling part since the first associated coupling part is separated fromthe first coupling part when the abutment is rotated with respect to thefixture.

Accordingly, in the present invention, the abutment and the fixture areseparated from each other with less force since the abutment isautomatically and upwardly pushed when the abutment is rotated withrespect to the fixture while the abutment and the fixture are coupled.Herein, the abutment may be easily separated from the fixture by beingupwardly pulled with respect to the fixture. In addition, in the presentinvention, the abutment is not re-coupled with the fixture underexcessive rotation since the abutment is automatically and upwardlypushed when the abutment is rotated with respect to the fixture.

In addition, according to the present invention, when separating theabutment from the fixture, the abutment is separated from the fixture,and is automatically and upwardly protruded when the abutment is rotatedwith respect to the fixture. Accordingly, the operator may easily detecta separation state between the abutment and the fixture. Thus, theimplant procedure may easily and conveniently progress withoutdifficulty and worry. In addition, according to the present invention,an additional polygonal form for a rotation prevention function is notprovided to the abutment. In addition, according to the presentinvention, when vertical occlusal force is applied to the abutment, theinclined surface may effectively absorb vertical occlusal pressure.

In addition, according to the present invention, a coupling positionbetween the fixture and the abutment may be easily found by forming afirst coupling part for a rotation prevention which is formed with acoupling hole downwardly extending from the top of an inclined surfaceof the axial hole inner surface of the fixture in which the firstcoupling part is formed. Accordingly, when the abutment is coupled withthe fixture by being inserted into the fixture axial hole, the firstcoupling part may guide a coupling protrusion of the associated couplingpart which is formed in a coupling leg of a lower part of the abutment.

DESCRIPTION OF DRAWINGS

FIG. 1 is an external perspective view showing a coupling structure inwhich an abutment of a coupling leg type is coupled to a fixture in adental implant according to the present invention.

FIG. 2 is a longitudinal sectional view showing a dental implantaccording to the present invention.

FIG. 3a is a sectional plan view of a first associated coupling partthat performs a rotation prevention function in the dental implantaccording to the present invention, and is a sectional plan view of FIG.2 along an A-A line.

FIG. 3b is a sectional plan view of a first coupling part that performsa rotation prevention function in the dental implant according to thepresent invention, and is a sectional plan view of FIG. 2 along a B-Bline.

FIG. 4a is a longitudinal sectional view showing a coupling intermediatestate between the abutment and the fixture in the dental implantaccording to the present invention.

FIG. 4b is a longitudinal sectional view showing a coupled state betweenthe abutment and the fixture in the dental implant according to thepresent invention.

FIG. 5a is a sectional planar view showing an intermediate couplingprocess between the abutment and the fixture in the dental implantaccording to the present invention.

FIG. 5b is a sectional planar view showing a coupled state between theabutment and the fixture in the dental implant according to the presentinvention.

FIG. 6a is a longitudinal sectional view showing a decouplingintermediate process between the abutment and the fixture in the dentalimplant according to the present invention.

FIG. 6b is a longitudinal sectional view showing a state in which theabutment is automatically and upwardly pushed from the fixture since thefirst associated coupling part that mainly performs a rotationprevention function is lifted up by the inclined surface of the fixturein the dental implant according to the present invention.

FIG. 7 is a longitudinal sectional view showing a structure of acoupling hole downwardly extending from the top of a fixture axial holeinner inclined surface according to another embodiment of the presentinvention.

MODE FOR INVENTION

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the accompanied drawings.

According to the present invention dental implant 100 according to thepresent invention includes a fixture 110 forming an artificial toothroot implanted in an alveolar bone (not shown), and an abutment 120coupled with the fixture 110 at a low part thereof and coupled with aprosthesis (crown or denture) at an upper part thereof. An implantprocedure is performed by elastically and detachably coupling thefixture 110 and the abutment 120 as shown in FIG. 1 and FIG. 2.

The dental implant 100 according to the present invention is formed inat least one coupling leg 122 that is formed in a lower part of theabutment 120 and inserted into the fixture 110. The dental implant 100includes a first associated coupling part 130 that mainly performs arotation prevention function with respect to rotation force equal to orless than a predetermined value. The first associated coupling part 130is formed with a circular coupling protrusion 132 on an associatedinclined surface formed in a lower outer surface of each coupling leg122. Herein, the associated inclined surface formed on the outer surfaceof the coupling leg that is formed in the lower part of the abutment mayhave or may not have an angle identical to an angle of an inclinedsurface formed in an axial hole inner surface of the fixture. Inaddition, the coupling protrusion may have a non-circular form. In otherwords, the coupling protrusion may have various forms in addition to thecircular form. For example, the coupling protrusion may have aband-shaped protruding part by a predetermined distance along acircumferential direction.

The first associated coupling part 130) that mainly performs a rotationprevention function with respect to the rotation force equal to or lessthan the predetermined value may be formed with, for example, a circularcoupling protrusion 132 formed in each of four coupling legs 122 asshown in a sectional planar view of FIG. 3, or may be formed in a partof the coupling legs (not shown).

In addition the dental implant 100 according to the present inventionincludes a fixture axial hole inner inclined surface 140 in which aninner diameter of an axial hole is gradually and downwardly reduced froma predetermined position in a vertical direction of an axial hole innersurface of the fixture.

In other words, the fixture axial hole inner inclined surface 140 has acone structure with a wide top and a narrow bottom from a predeterminedposition towards a lower part of the axial hole inner surface of thefixture 110.

In addition, the dental implant 100 according to the present inventionincludes a first coupling part 150 that performs a rotation preventionfunction by being outwardly depressed on the fixture axial hole innerinclined surface 140 and complementarily coupled with the firstassociated coupling part 130. Herein, vertical lengths of the firstassociated coupling part and the first coupling part may be different.However, horizontal distances thereof in a circumferential directionshould be identical within a numerical mechanical tolerance. Thereby,there will be no excessive micro-fluctuations for rotation force equalto or less than a predetermined value.

The first coupling part 150 may be formed with a circular coupling hole152 that is complementarily coupled in association with the circularcoupling protrusion 132 of the first associated coupling part 130 formedin the inclined surface 140. Herein, a form of the coupling hole or thecoupling protrusion may vary, and a form of each first associatedcoupling part formed in each coupling leg may not be identical.Accordingly, a form of a first coupling part complementarily couplingwith the first associated coupling part may be different.

In addition, in order to easily find a coupling position of the fixtureand the abutment, the first coupling part may be formed with a couplinghole downwardly extending from the top of the inclined surface. Herein,the coupling hole of the first coupling part and the coupling protrusionof the first associated coupling part may be identical within anumerical error of machining so that the coupling hole of the firstcoupling part and the coupling protrusion of the first associatedcoupling part may be coupled in a female and male type. However,vertical lengths of the coupling hole and the coupling protrusion maynot be identical.

The first coupling part 150 that mainly performs a rotation preventionfunction may be formed with, for example, four circular coupling holes152 associated with respective first associated coupling parts 130formed with four circular coupling protrusions 132 as shown in asectional planar view of FIG. 3 b.

Hereinafter, with reference to the figure, a structure in which thefirst associated coupling part 130 is formed with a circular couplingprotrusion 132, and a first coupling part 150 is formed with a circularcoupling hole 152 coupled in association with the circular couplingprotrusion 132 of the first associated coupling part 130 will bedescribed in detail. Persons skilled in the art may easily know that anidentical coupling and separating process may be applied to a structurein which the first associated coupling part 130 is formed with acircular coupling hole (not shown), and the first coupling part 150 isformed with a circular coupling protrusion (not shown) that is coupledin association with the circular coupling hole. The present inventionshould be construed to include both structures.

In addition, the present invention may additionally include a secondassociated coupling part 160 that is protruded radially outwardly fromthe abutment 120 and formed in a lower part or an upper part of thefirst associated coupling part 130, and mainly performs a verticalseparation prevention function.

In addition, in the present invention, the first coupling part and firstassociated coupling part may additionally perform functions of a secondcoupling part and the second associated coupling part.

In the second associated coupling part 160 that mainly performs avertical separation prevention function, as shown in FIG. 2, an uppersectional surface of a coupling protrusion protruding radially outwardlyfrom the abutment 120 forms a coupling planar surface 162 of the secondassociated coupling part, and a longitudinal sectional surface of thesecond associated coupling part that mainly performs a vertical separateprevention function by the coupling protrusion may be formed with asectional surface in which a radius thereof is downwardly reduced.

In addition, in the axial hole inner surface of the fixture, a secondcoupling part 170 that is formed with a holding portion with a concaveshape formed radially inwardly, and which is coupled in association withthe second associated coupling part 160 may be further included.

In addition, the first coupling part and the second coupling part may beintegrated and configured in a single coupling part.

The second coupling part 170 formed with the holding portion asdescribed above has a structure that includes a coupling planar surface172 of the second coupling part which is associated with the couplingplanar surface 162 of the second associated coupling part 160 thatmainly performs a vertical separation prevention function. In addition,an angle formed where the coupling planar surface of the second couplingpart and the coupling planar surface of the second associated couplingpart meet a vertical central axis 1 may vary.

The second associated coupling part 160 and the second coupling part 170as descried above, as shown in FIG. 4a , become automatically separatedfrom each other since the coupling leg 122 is elastically bent radiallyinwardly when the first associated coupling part 130 is detached andseparated from the first coupling part 150.

However, when the first associated coupling part 130 and the firstcoupling part 150 are coupled, as shown in FIG. 4b , the secondassociated coupling part 160 and the second coupling part 170 aresimultaneously coupled so that axial directional coupling force betweenthe abutment 120 and the fixture 110 is reinforced. Accordingly, thesecond associated coupling part and the second coupling part whichmainly perform a vertical separation prevention function may maintainvertical separation prevention coupling force without any damage duringrepeated detachments.

In addition, the first associated coupling part 130 formed with thecoupling protrusion 132 is formed on an associated inclined surface 180formed in a lower outer surface of each coupling leg 122, and coupled inassociation with the coupling hole 152 of the first coupling part 150.

The associated inclined surface 180 of the coupling leg 122 in which thefirst associated coupling part 130 is formed may be formed to have aslope identical to a slope of the inclined surface 140 of the axial holeof the fixture 110 in which the first coupling part 150 is formed.

In the dental implant 100 of the present invention configured as above,the abutment 120 is completely pushed into an axial hole 112 of thefixture 110 as shown in FIG. 4a and FIG. 5a , and the abutment 120 isrotated in a circumferential direction in order to couple the abutment120 with the fixture 110.

Accordingly, the circular coupling protrusion 132 of the firstassociated coupling part 130 formed in each coupling leg 122 of theabutment 120 is coupled in association with the circular coupling hole152 of the first coupling part 150 formed on the inclined surface 14) ofthe fixture 110 as shown in FIG. 4b and FIG. 5 b.

Alternatively, in order to separate the abutment 120 from the fixture110 while the abutment 120 and the fixture 110 are coupled, the abutment120 is rotated in a circumferential direction within the fixture 110.

The above state is shown in FIG. 6a . In other words, in the dentalimplant 100) of the present invention, the first associated couplingpart 130 comes out and is separated from the first coupling part 150 ina circumferential direction by rotating the abutment 120 in acircumferential direction while the abutment 120 is coupled within thefixture 110. At the same time, the second associated coupling part 160that mainly performs a vertical separation prevention functionautomatically comes out from the second coupling part 170.

Accordingly, w en the first associated coupling part 130 that mainlyperforms a rotation prevention function of the abutment in acircumferential direction with respect to the abutment is rotated in acircumferential direction and separated from the first coupling part 150by rotation force equal to or greater than a predetermined value, andthe second associated coupling part 160 that mainly performs a verticalseparation prevention function is come out from the second coupling part170, the coupling leg 122 is inwardly bent (direction in an innerdiameter), thus the coupling protrusion of the first associated couplingpart 130 pushes against the axial hole inner inclined surface 140 of thefixture 110 by elastic restoring force.

Accordingly, the first associated coupling part 130 is upwardly slippedin the fixture axial hole inner inclined surface 140, and upwardlypushes the abutment 120 from the fixture 110 as shown in FIG. 6b , thusthe abutment 120 and the fixture 110 become separated.

As described above, according to the present invention, when separatingthe abutment 120 from the fixture 110, the abutment 120 is easilyseparated from the fixture 110 since the first associated coupling part130 is separated from the first coupling part 150 when the abutment 120is rotated with respect to the fixture 110, and the abutment 120 isupwardly pushed from the fixture 110 by elastic repulsion with theinclined surface 140.

Accordingly, in the present invention, the abutment 120 may be separatedfrom the fixture 11 with less force, whereby a large pulling force maynot be applied to an alveolar bone of a patient as in the past. Inaddition, a decrease in vertical separation prevention coupling force ofthe abutment with respect to the fixture does not occur when theabutment is repeatedly attached to and detached from the fixture.Further, the abutment is not re-coupled with the fixture although arotation amount is large since the abutment is automatically andupwardly pushed when the first associated coupling part is separatedfrom the first coupling part.

As described above, according to the present invention, it is possibleto minimize the risk of injury to the patient during the implantprocedure, and an operator may easily determine a separation statebetween the abutment 120 and the fixture 110 since the abutment 120 isautomatically pushed up from the fixture 110. Accordingly, an implantoperator may easily and conveniently progress the procedure withoutdifficulty and worry.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it is to be understood that theinvention is not limited to this specific structure. Rather,modifications and changes will be apparent to a person having ordinaryskill in the art without departing from the principle of the inventiondefined in the following claims. For example, strong rotation force maybe applied to the fixture by forming a polygonal form in the axial holeinner surface of the fixture or a lower part thereof when implanting thefixture in the alveolar bone. For example, a single coupling part inwhich functions of the first coupling part and the second coupling partare integrated may be formed. Herein, the structure, that is configuredto enable easy separation of the abutment from the fixture by contactingthe associated coupling part formed in the lower part of the abutmentwith the axial hole inner inclined surface formed in the axial holeinner surface of the fixture, and by upwardly pushing the abutment byelastic repulsion when the abutment is rotated while the abutment iscoupled with the fixture is not changed. In addition, forms of the firstcoupling part and the first associated coupling part that mainlyperforms a rotation prevention function and the first associatedcoupling part may be not associated 100%. In other words, although theforms of the first coupling part first associated coupling part do notcomplementarily associate 100%, it is only necessary to be able toperform a rotation prevention function for rotation force equal to orless than a predetermined value. As another example, both of the firstand second associated coupling parts may not be formed in the couplingleg. In other words, the first and second associated coupling parts maybe formed in a part of the coupling legs. As another example, the firstcoupling part or the first associated coupling part which are circularmay have various forms other than a circular form. In addition, fourcoupling legs 122 are formed in the example of the figure. However, oneto six or more coupling legs 122 may be formed, and the first associatedcoupling part 130 may be formed in each coupling leg 122. In associationwith this, the first coupling part 150) may be formed. In addition, thesecond coupling part may have various coupling angles and formsdepending on the vertical central axis. In other words, the planarsurface of the second associated coupling part may be formed to have agradual angle rather than the planar surface. In addition, as anotherexample, the inclined surface in which the first coupling part is formedmay be formed in a stepped form rather than a continuous surface.Meanwhile, whichever coupling method in which the abutment is coupledwith the fixture, as the method in which the coupling protrusion and thecoupling hole are elastically coupled with each other by elasticrepulsion thereof, it should be construed that the structure, in whichthe abutment and the fixture are easily separated by upwardly pushingthe abutment from the fixture by elastic repulsion between the couplingprotrusion of the associated coupling part formed in the lower part ofthe abutment and the inclined surface formed in the axial hole innersurface of the fixture when the abutment is rotated while the abutmentis coupled with the fixture, is included in the scope of the presentinvention. In other words, it should be construed that all cases inwhich the first coupling part formed with the coupling hole in theinclined surface of the axial hole inner surface of the fixture andwhich is elastically coupled with the abutment is included, and theabutment and the fixture are easily separated from each other, byupwardly pushing the abutment from the fixture by elastic interactionbetween the inclined surface of the axial hole inner surface of thefixture and the first associated coupling part formed in the lower partof the abutment when the abutment is rotated with respect to the fixturewhile the abutment and the fixture are coupled with each other since thefirst associated coupling part is formed in the abutment in associationwith the first coupling part are included in the scope of the presentinvention. In addition, a simple design modification including technicalcharacteristic of the present invention may be included within thespirit and scope of the present invention.

DESCRIPTION OF REFERENCE NUMERALS

-   -   100: dental implant    -   110: fixture    -   112: axial hole    -   120: abutment    -   122: coupling leg    -   130: first associated coupling part    -   132: circular coupling protrusion    -   140: fixture axial hole inner inclined surface    -   150: first coupling part    -   142: coupling hole    -   160: second associated coupling part    -   162: coupling planar surface of second associated coupling part    -   170: second coupling part    -   172: coupling planar surface of second coupling part couple    -   180: associated inclined surface    -   1: vertical central axis

What is claimed is:
 1. A dental implant, comprising: a) a fixture havingan axial hole with an inner inclined surface in which an inner diameterof the axial hole is gradually and downwardly reduced from apredetermined position in the inner inclined surface the fixture furtherincluding a first coupling part in the form of a coupling recess formedin the inner inclined surface along a circumferential direction; and b)an abutment including at a lower part thereof a coupling leg thatincludes on an outer surface thereof a first associated coupling partwith a respective coupling protrusion for coupling elastically to thefirst coupling part when the abutment is coupled within the fixture onlywhen the abutment is inserted into the fixture at a predetermined angle,wherein the first coupling part is formed at a position corresponding tothe coupling protrusion, wherein in a state in which the abutment isfitted into the fixture by complementary coupling between the firstcoupling part and the first associated coupling part, when a rotationforce applied to the abutment has less than a predetermined value, theabutment is presented from rotating relative to the fixture in thecircumferential direction, and wherein when the rotation force appliedto the abutment is equal to or greater than the predetermined value, thecoupling leg of the abutment is elastically bendable radially inwardlytoward a central axis and the abutment can be rotated relative to thefixture in the circumferential direction so that the coupling protrusionis separated from the coupling recess, whereby the coupling protrusionpushes upwardly the abutment by elastic repulsion with the innerinclined surface, thus causing the abutment and the fixture toautomatically be separated from each other.
 2. The dental implant ofclaim 1, wherein the coupling recess is circular.
 3. The dental implantof claim 1, wherein the coupling recess is non-circular.
 4. The dentalimplant of claim 1, wherein the fixture further includes a secondcoupling part formed at the bottom of the inner inclined surface alongthe circumferential direction, with a holding portion extending inwardlyfrom the inner inclined surface, wherein the abutment further includes asecond associated coupling part formed with an associated holdingprotrusion protruding outwardly from the outer surface of the couplingleg, and wherein the second coupling part is coupled elastically withthe holding protrusion of the second associated coupling part to preventa vertical separation of the abutment from the fixture.
 5. The dentalimplant of claim 2, wherein the fixture further includes a secondcoupling part formed at the bottom of the inner inclined surface alongthe circumferential direction, with a holding portion extending inwardlyfrom the inner inclined surface, wherein the abutment further includes asecond associated coupling part formed with an associated holdingprotrusion protruding outwardly from the outer surface of the couplingleg, and wherein the second coupling part is coupled elastically withthe holding protrusion of the second associated coupling part to preventa vertical separation of the abutment from the fixture.
 6. The dentalimplant of claim 3, wherein the fixture further includes a secondcoupling part formed at the bottom of the inner inclined surface alongthe circumferential direction, with a holding portion extending inwardlyfrom the inner inclined surface, wherein the abutment further includes asecond associated coupling part formed with an associated holdingprotrusion protruding outwardly from the outer surface of the couplingleg, and wherein the second coupling part is coupled elastically withthe holding protrusion of the second associated coupling part to preventa vertical separation of the abutment from the fixture.
 7. A method forusing a dental implant, comprising: a) providing a fixture comprising anaxial hole with an inner inclined surface in which an inner diameter ofthe axial hole is gradually and downwardly reduced from a predeterminedposition in the inner inclined surface, wherein the inner inclinedsurface includes a first coupling part in the form of a coupling recessalong a circumferential direction: b) providing an abutment comprisingat a lower part thereof a coupling leg that includes on an outer surfacethereof a first associated coupling part with a respective couplingprotrusion: c) fixedly attaching the abutment to the fixture by couplingthe coupling protrusion elastically to the coupling recess such that thefixedly attached abutment is prevented solely by elastic coupling fromrotating relative to the fixture in a circumferential direction when arotation force applied to the fixedly attached abutment has less than apredetermined value; and d) separating the fixedly attached abutmentfrom the fixture by applying to the fixedly attached abutment a rotationforce equal to or greater than the predetermined value to rotate theabutment in the circumferential direction to separate the couplingprotrusion from the coupling recess.
 8. The method of claim 7, whereinthe applying to the fixedly attached abutment a rotation force equal toor greater than the predetermined value to rotate the fixedly attachedabutment in the circumferential direction includes elastically bendingthe coupling leg radially inwardly to separate the coupling protrusionfrom the coupling recess.
 9. The method of claim 7, wherein the fixturefurther comprises a second coupling part formed at the bottom of theinner inclined surface along a circumferential direction with a holdingportion extending inwardly from the inner inclined surface, wherein theabutment further comprises a second associated coupling part formed withan associated holding protrusion protruding outwardly from the outersurface of the coupling leg, wherein the fixedly attaching the abutmentto the fixture includes engaging the second coupling part with thesecond associated coupling part, and wherein the separating the fixedlyattached abutment from the fixture includes disengaging the secondcoupling part from the second associated coupling part to enablevertical extraction of the fixedly attached abutment from the fixture.10. The method of claim 8, wherein the fixture further comprises asecond coupling part at a bottom section of the axial hole, wherein theabutment further comprises a second associated coupling part at an endsection of the coupling leg, wherein the fixedly attaching the abutmentto the fixture includes engaging the second coupling part with thesecond associated coupling part, and wherein the elastically bending thecoupling leg radially inwardly to separate the coupling protrusion fromthe circular coupling recess disengages the second coupling part fromthe second associated coupling part to enable vertical extraction of thefixedly attached abutment from the fixture.